1. Field of Invention
The present invention relates generally to the field of input devices. More specifically, the present invention relates to keyboard input devices designed to occupy a relatively small area so as to be particularly applicable to portable or hand-held electronic devices.
2. Discussion of Prior Art
For many electronic devices which require keyboard inputs, a conventional keyboard is not practical. Most portable devices are designed to be small enough so as to be convenient for the user to carry them without undue burden. Pagers, cellular phones and palm top PCs are typically designed to fit into a shirt pocket while portable PCs are designed to be conveniently carried by the user in a small case or bag. These devices have limited surface space and accordingly their keyboards are designed with reduced sized keys, with fewer character keys, or the keys are arranged in a different manner than the traditional QWERTY style keyboard. Some devices are operated using a stylus interface. The user points the stylus at one character at a time on a graphic display of a keyboard in order to select the character.
While a number of solutions to the keyboard issues have been proposed, most of them are complicated for users familiar with the traditional QWERTY style keyboard. One solution requires the user to remember unique combinations of keys, as indicated in U.S. Pat. No. 5,493,654, “Chordic Keyboard System for Generating a Signal in Response to a Chord That is Assigned Using a Correlation Based on a Composite Chord-Difficulty Index” and U.S. Pat. No. 4,911,565, “Device for One-Handed Generation of Alpha-Numeric Characters”. Other solutions provide for complicated micro keypads, as in U.S. Pat. No. 5,841,374, “Micro Word-Pad with Tactile Multifunctional Keys”.
The QWERTY style keyboard developed due to the initial mechanics utilized in early typewriters. The layout of the symbols on early typewriters (i.e., QWERTY style) were placed in such a manner so as to slow the typist down. By slowing the typist down, mechanical problems were prevented. In recent years, however, the mechanical limitations imposed by the early typewriters have essentially disappeared. As such, there have been efforts to create layouts and keyboards which more effectively utilize the letter sequences most utilized in the English language so that the typists flow is not impeded. One such proposed solution is the so-called Dvorak keyboard. Another keyboard which seeks to provide more efficient key layouts is described in U.S. Pat. No. 4,333,097, by Buric et al. An additional goal of this patent is to eliminate the need for the typist to move their fingers from the keys. Disclosed is a new keyboard structure interface which utilizes a set of eight input keys, one for each finger, and two scrolling keys, one for each thumb. The keyboard is utilized with a display, part of which displays the current input key assignments. The user uses an input key to enter the corresponding symbol assigned to that key. By actuating the scrolling buttons, the user can scroll, up or down, among a set of alternate symbol assignments for the input keys. The choice of symbol assignments (and therefore the ultimate “keyboard layout”) is arranged in a manner which seeks to balance the relative frequency of symbols common in the English language with the relative strengths of the user's fingers. The keyboard of Buric seeks to depart from the traditional QWERTY style keyboard, unlike one embodiment of the present invention. The provision of eight keys (one for each finger) and the two scrolling keys (one for each thumb) prevents the use of a QWERTY style layout, as there are ten keys per row on a QWERTY keyboard. Significant disadvantages result from the lack of support for a QWERTY style layout. Even though more efficient key layouts exist, the QWERTY keyboard is still the most popular layout for keyboards. A such, keyboard users are most familiar with the QWERTY keyboard and significant learning barriers are incurred when a user not only has to learn a new interface structure, but has to learn a new key layout in addition.
Similar to the keyboard of Buric, the keyboard of Kamei, et al., U.S. Pat. No. 4,481,508, provides ten physical keys for character entry and scrolling keys to change the symbols assigned to the keys for character entry, however, the patent to Kamei teaches scrolling through the characters in a sequential manner and does not provide for a QWERTY style layout. Therefore, the speed of touch typing is significantly reduced as users are not familiar with a sequential type key layout and must relearn not only the interface structure, but the sequential key layout in addition. In addition, the patents of Buric and Kamei et al. do not provide for key placements on the corresponding devices and other innovations of the present invention which effectively allow for an increase in display area.
Some products are known which address the need for keyboard input to portable or hand-held electronic devices. Think Outsider™ produces a product known as the Stowaway™ Portable Keyboard. This is a full sized keyboard which folds down to a size with which it is capable to place in a persons pocket. The keyboard is designed so as to be unfolded and attached to the Palm™ PDA. Another product is an external keyboard which connects to a cellular phone made by NTT DoCoMo. Both of these suffer from the disadvantages of being larger than what would be desired for an input to a portable device and from the needed assembly to utilize the keyboards.
As described, the above products demonstrate the needs and difficulties of providing keyboard input to portable or hand-held electronic devices. Ideally, the keyboard input should be able to be affected in as natural a manner and as close to what users are accustomed to as possible. In addition, however, it is desirable for the keyboard to be as small as possible to allow for portability and to increase the allowable area to implement displays. However, the keys of the keyboard still need to be large enough for good ergonomic use.
Another attempt at solving the above difficulties is demonstrated by U.S. Pat. No. 5,515,305 by Register et al. The PDA of Register has eight keys located on the back thereof. When the user grasps the PDA, each finger can contact a key. The input method of the keyboard of Register is a chordic style keyboard. While this allows a larger set of characters to be represented by fewer keys, allowing for the keys to be large enough for good ergonomic use and providing an overall smaller keyboard, chordic keyboards require a user to remember unique key combinations to input a character. To provide the same functionality as a standard keyboard such as those used with many present personal computers, a user must remember 101 different key combinations. In general, this is a significant amount of information for a user to remember in order to input characters to the electronic device and creates a significant learning barrier, especially as most users are used to actuating a single key to input a character. Hence, unlike the present invention, the chordic is a less natural means of inputting characters.
As the real estate war between display and keyboard on PDAs and other portable computing devices continues, keyboards will lose as displays increase in resolution, color, and attractiveness. Simply scaling down a fall size keyboard creates keys which are too small for good ergonomic use. There is still a need for a user friendly keyboard type input which supports the traditional QWERTY style layout and which allows for a significant reduction in effective size. In addition, there is still a need for keyboards which provide a more natural input style for users of portable or hand-held electronic devices and which allow for faster input, while still providing possible reduction in overall keyboard size and in which the keys can be maintained at appropriate sizes for good ergonomic use.